1. Field of the Invention
The present invention relates to a piezoelectric actuator and a method of producing the piezoelectric actuator. The present invention, more specifically, relates to a piezoelectric actuator which has satisfactory piezoelectric characteristics, a method of producing such piezoelectric actuator, and a method of producing an ink-jet head.
2. Description of the Related Art
An example of a piezoelectric actuator used in ink-jet head or the like is described in Japanese Patent Application Laid-open Publication No. 2001-54946. In this piezoelectric actuator, a substrate (a vibration plate) is provided such that an opening of a pressure chamber which communicates with a nozzle opening in a channel forming body, and a lower electrode, a piezoelectric layer, and an upper electrode are laminated on this substrate. When an electric field is applied between the upper electrode and the lower electrode, the substrate is bent with the deformation of the piezoelectric layer. Due to this, ink in the pressure chamber is pressurized and is discharged from the nozzle opening.
Such a piezoelectric actuator is manufactured, for example, as described below. First of all, a metal paste such as Pt paste is coated on the substrate, and calcinated to form a lower electrode. Next, a piezoelectric layer is formed on this lower electrode by an aerosol deposition method (AD method). In the aerosol deposition method, a substance in which fine particles of a piezoelectric material such as lead zirconate titanate (PZT) are dispersed in a gas is jetted toward a surface of the substrate, and the fine particles are allowed to be collided and to be deposited on the substrate. Thus, the piezoelectric layer is formed.